Means for the automatic equilibrium of floating cranes



V. LOCARNI.

MEANS FOR THE AUTOMATIC EQUiLIBRIUM 0F FLOATING CRANES.

APPLICATION FILED MAY 31, ms.

Patented June 15, 1920.

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ATTORNEY UNITED STATES PATENT OFFICE.

VITTOBIO IQOGARNI, OF GENOA, ITALY, ASSIGNOR TO SOCIETA ANONIMA ITALIANA GIO. ANSALDO & 0., OF GENOA, ITALY.

MEANS FOR THE AUTOMATIC EQUILIBRIUM OF FLOATING GRANES.

Specification of Letters Patent.

Patented June 15, 1920.

Application filed May 31, 1919. Serial No. 300,883.

To all whom it may concern:

Be it known that I, Vrrronro LooARNI, of Genoa, Italy, have invented certain new and useful Improvements in Means for the Automatic Equilibrium of Floating Cranes, of which the following is a specification.

My invention relates to improvements in electro-mechanic devices for the automatic equilibrium of the floating cranes.

Forthe purpose of illustrating my invention I have shown in the accompanying drawings one form thereof which is at present preferred by me, although it is to be understood. that the various parts forming the invention can be variously arranged and organized, and that my invention is not limited to the precise arrangement and organization of these parts as herein shown and described.

Figure 1 is a view of a floating crane with the invention applied to it;

Fig. 2 is a diagram of the arrangement of the several instruments of the electromechanic device for the automatic equilibrium of the crane.

Referring to Fig. 1, it shows a floating crane, where a indicates the suspension hook, which can be moved along the crane arm to occupy any position between --a and -a-; -Z)- is the counterweight which can be displaced to any position between -band b'-. The arrangement of the parts is designed to obtain that with any load applied to the hook -a' and with the said load applied to a point in any position between -a and athe equilibrium or horizontal position of the crane, can be maintained through the displacing of the counterweight from --b-- to -Z).

Purpose of the invention is to have the counterweight b occupy automatically the right position for the equilibrium of the crane.

This is obtained by the system illustrated in Fig. 2, in which -cis a direct current electric motor shunt excited which drives a direct current electric generator --0Z- excited with a separate shunt --e-.

The armature of the enerator cZ is directly connected with the armature of an electric motor which has a constant shunt excitation. This motor --f is suitably geared through gears --gwith the treaded shaft -hfor producing the dis placement of the counterweight mass from one to the other end of its travel viz from position -71- to b.

The automatic regulation of the motor f is given by the resistance Z-- over which slides the arm of contacts mpivoted in p and forming part of the rod ---nto which is attached the weight 0. Purpose of the weight is to maintain the arm -m in a fixed position with relation to the vertical, regardless of the inclination that the crane may assume.

The resistance Z- is formed so that when the arm -777r* rotates from its neutral. position, it allows a gradual How of current through the induced circuit -e-- in one direction or in the other, thus producing a gradual rotation of the motor fin one direction or the other, which rotation is transmitted to the screw -k.- This produces of course the displacement of the counterweight -Z toward one direction or the other according to the greater or less inclination of the crane with relation to the vertical plane of the pendulum n-- --0-.

The speed of the motor f-- is consequently a function of the relative displacement of the arm m-- with relation to the neutral position of the resistance Z--.

()bviously, as soon as the crane inclines from its vertical center line, the system gives origin to a relative displacement between the arm mand the resistance contacts -Z- with relation to the neutral position, which displacement increases directly with the inclination.

Of course as soon as the motor -f starts to rotate the counterweight is displaced till, by restablishing the position of equilibrium of the crane the displacement between the resistance contacts Z- and the arm mhas been reduced to zero bringing the motor to a stop.

As shown by Fig. 1, the counter weight -bmoves along the same plane but in the opposite direction, of the hook a-.'

Having now particularly described and ascertained in the nature of my said invention and in what manner the same is to be performed, what I claim is:

1. An electromechanic device for the automatic equilibrium of floating cranes, comprising a moving counterweight mass, a screw engaging said mass, and an electric motor for rotating through gearing the screw, the armature of the said motor being electrically connected to a direct current generator, both the motor and the generator being provided with fields in shunt.

2. An electromechanic device for the automatic equilibrium of floating cranes, comprising a moving counterweight, a screw for displacing the said counterweight a motor for'driving the screw, a second motor for driving the generator supplying the current to the first motor, a starting and reversing resistance to control the field of the said first motor and of the generator said resistance being controlled by a pivoted arm of contacts forming a whole with a pendulum, the said pendulum keeping the arm in its neutral position when the crane is vertical.

In testimony whereof I have hereunto signed my name in the presence of two witnesses.

VITTORIO LOCARNI. Witnesses:

AACDEB ALEART, ALEXANDER WERE. 

